Herman and his Hermits are going after their fourth gold record with "Something's Happening" (K-14035), their latest MGM single. An instant Top 10 smash in England, the group's new lightly Latin sound was already showing signs of similar success in its Stateside release last week. Also happening: the soundtrack album from their MGM movie, "Mrs. Brown You've Got A Lovely Daughter" (SE-4548 ST.)